[PATCH net-next] tcp: preserve const qualifier in tcp_rsk() and inet_rsk()

[PATCH net-next] tcp: preserve const qualifier in tcp_rsk() and inet_rsk()

[Eric Dumazet]

We can change tcp_rsk() and inet_rsk() to propagate their argument
const qualifier thanks to container_of_const().

Signed-off-by: Eric Dumazet <edumazet@google.com>
---
 include/linux/tcp.h              | 5 +----
 include/net/inet_sock.h          | 5 +----
 include/trace/events/tcp.h       | 2 +-
 net/ipv4/inet_connection_sock.c  | 2 +-
 net/ipv6/inet6_connection_sock.c | 2 +-
 5 files changed, 5 insertions(+), 11 deletions(-)

diff --git a/include/linux/tcp.h b/include/linux/tcp.h
index 20b8c6e21fef36984810541a06fcb7ba8f0c45b1..367b491ddf978061d5a88ab02546ec99be1cca63 100644
--- a/include/linux/tcp.h
+++ b/include/linux/tcp.h
@@ -181,10 +181,7 @@ struct tcp_request_sock {
 #endif
 };
 
-static inline struct tcp_request_sock *tcp_rsk(const struct request_sock *req)
-{
-	return (struct tcp_request_sock *)req;
-}
+#define tcp_rsk(ptr) container_of_const(ptr, struct tcp_request_sock, req.req)
 
 static inline bool tcp_rsk_used_ao(const struct request_sock *req)
 {
diff --git a/include/net/inet_sock.h b/include/net/inet_sock.h
index 3370159556b8602d1ceef06c0c742479452602df..903b2263ec8031565990dc52b921352e6a642b1a 100644
--- a/include/net/inet_sock.h
+++ b/include/net/inet_sock.h
@@ -100,10 +100,7 @@ struct inet_request_sock {
 	};
 };
 
-static inline struct inet_request_sock *inet_rsk(const struct request_sock *sk)
-{
-	return (struct inet_request_sock *)sk;
-}
+#define inet_rsk(ptr) container_of_const(ptr, struct inet_request_sock, req)
 
 static inline u32 inet_request_mark(const struct sock *sk, struct sk_buff *skb)
 {
diff --git a/include/trace/events/tcp.h b/include/trace/events/tcp.h
index 6757233bd0641778ce3ee260c9d757070adc0fcf..f155f95cdb6e910b8718e11d32d150cff8de3266 100644
--- a/include/trace/events/tcp.h
+++ b/include/trace/events/tcp.h
@@ -305,7 +305,7 @@ TRACE_EVENT(tcp_retransmit_synack,
 	),
 
 	TP_fast_assign(
-		struct inet_request_sock *ireq = inet_rsk(req);
+		const struct inet_request_sock *ireq = inet_rsk(req);
 		__be32 *p32;
 
 		__entry->skaddr = sk;
diff --git a/net/ipv4/inet_connection_sock.c b/net/ipv4/inet_connection_sock.c
index 97d57c52b9ad953d7ec1ad679237b5d122f47470..13372d2cbed53e83510e24a34bc57c7de0a17004 100644
--- a/net/ipv4/inet_connection_sock.c
+++ b/net/ipv4/inet_connection_sock.c
@@ -1196,7 +1196,7 @@ struct sock *inet_csk_clone_lock(const struct sock *sk,
 {
 	struct sock *newsk = sk_clone_lock(sk, priority);
 	struct inet_connection_sock *newicsk;
-	struct inet_request_sock *ireq;
+	const struct inet_request_sock *ireq;
 	struct inet_sock *newinet;
 
 	if (!newsk)
diff --git a/net/ipv6/inet6_connection_sock.c b/net/ipv6/inet6_connection_sock.c
index ea5cf3fdfdd648e43f4c53611f61509ce06d4cf8..3aedd51c9bdb18b3b45ff3f6b56666e2ffd1f515 100644
--- a/net/ipv6/inet6_connection_sock.c
+++ b/net/ipv6/inet6_connection_sock.c
@@ -29,7 +29,7 @@ struct dst_entry *inet6_csk_route_req(const struct sock *sk,
 				      const struct request_sock *req,
 				      u8 proto)
 {
-	struct inet_request_sock *ireq = inet_rsk(req);
+	const struct inet_request_sock *ireq = inet_rsk(req);
 	const struct ipv6_pinfo *np = inet6_sk(sk);
 	struct in6_addr *final_p, final;
 	struct dst_entry *dst;
-- 
2.52.0.457.g6b5491de43-goog

Re: [PATCH net-next] tcp: preserve const qualifier in tcp_rsk() and inet_rsk()

[Kuniyuki Iwashima]

On Tue, Jan 20, 2026 at 4:53 AM Eric Dumazet <edumazet@google.com> wrote:
>
> We can change tcp_rsk() and inet_rsk() to propagate their argument
> const qualifier thanks to container_of_const().
>
> Signed-off-by: Eric Dumazet <edumazet@google.com>

Reviewed-by: Kuniyuki Iwashima <kuniyu@google.com>

Re: [PATCH net-next] tcp: preserve const qualifier in tcp_rsk() and inet_rsk()

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (main)
by Jakub Kicinski <kuba@kernel.org>:

On Tue, 20 Jan 2026 12:53:53 +0000 you wrote:
> We can change tcp_rsk() and inet_rsk() to propagate their argument
> const qualifier thanks to container_of_const().
> 
> Signed-off-by: Eric Dumazet <edumazet@google.com>
> ---
>  include/linux/tcp.h              | 5 +----
>  include/net/inet_sock.h          | 5 +----
>  include/trace/events/tcp.h       | 2 +-
>  net/ipv4/inet_connection_sock.c  | 2 +-
>  net/ipv6/inet6_connection_sock.c | 2 +-
>  5 files changed, 5 insertions(+), 11 deletions(-)

Here is the summary with links:
  - [net-next] tcp: preserve const qualifier in tcp_rsk() and inet_rsk()
    https://git.kernel.org/netdev/net-next/c/a4674aa58be5

You are awesome, thank you!
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